A variety of compounds constituting anticancer agents are currently developed by examining a derivation and a chemical structure thereof. Amid a growing demand for such new anticancer agents, anticancer agent development is constantly required due to such problems as side effects of an anticancer agent, generation of drug-resistant cancer cells caused by long-term use of anticancer agents and different medicinal effects by the type of cancer.
In fact, seaweed or unicellular algae is known as a natural resource required for providing an anticancer agent or candidate compounds thereof. A macrolide compound produced by dinoflagellate alga (Amphidinolide) particularly receives much academic attention due to a strong antitumor activity (Non-patent document 1). Because of the above-mentioned problems, however, seeking and development of anticancer agents, marine organism-derived antitumor substances in particular, is always regarded as a crucially important issue.
[Non-patent document 1] J. Kobayashi, et. al., teterahedron Lett., Vol. 27, p 5755, 1986